The present invention relates to a stackable, soil confinement grid material. Specifically the present invention relates to a grid material which can be stacked up and filled with soil to create free standing walls and similar structures.
A grid section of cells used for soil confinement to provide a road base made from soils (sand, rounded rock, poorly graded aggregate, concrete, and the like) has been known and used for some time. A prime example is Geoweb.TM. plastic grid soil confinement system, sold by Presto Products, Incorporated, P.0. Box 2399, Appleton, Wis. 54913. Geoweb.TM. grid cells are made from plastic strips which are joined on their faces in a side by side relationship at alternating spacings so that when the strips are stretched out in a direction perpendicular to the faces of the strips, the resulting grid section is honeycomb-like in appearance, with sinusoidal or undulent shapped cells.
Voluminous reports have praised the ability of Geoweb.TM. grid cell material to support roadways. Geoweb.TM. grid cells have also been used in applications where one grid layer is stacked on another, such as a stepped back design for hill slope retention. Even free standing walls have been built with Geoweb.TM. grid cells. However, because the cells are open on top and bottom, there is a tendency for fill material to leak out of the cells if the cell below is not properly positioned. Also, the exposed soil in a cell not adequately covered is subject to being blown away by the wind.
In an effort to overcome these problems, free standing structures have been built with alternating layers of grid confinement cells and sheet material, such as water permeable fabric. While this approach has helped to cover the exposed open tops and bottoms of the cells, it has not been completely successful, and, more importantly, requires the additional use of the separate sheet material.